Traynor Bass Master Mk II YBA-1A - Bright preset

Verified · 90/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The YBA-1A Bass Master Mk II is the higher-powered Bass Master head Traynor introduced in 1968. Two channels, each with two inputs and its own volume, mix into a 12AX7 gain stage and a shared treble/bass stack with a Low Range Expander, while a High Range Expander sits in the negative-feedback loop. A 12AX7 long-tail inverter drives two fixed-bias 6CA7s from a silicon supply. Guitarists also value it as a loud, punchy valve head.

• Introduced: 1968
• Made in: Canada
• Wattage: 90W
• Channels: 2
• Preamp tubes: 3× 12AX7
• Power tubes: 2× 6CA7

Tags: canadian, vintage, bass, el34, two-channel, mid-wattage.

Schematic-derived preset files for 16 Fractal and Line 6 modelers: Axe-Fx II/XL/XL+, Axe-Fx III, FM3, FM9, and the full Helix family (Floor, LT, Rack, HX Stomp, HX Stomp XL, Native).

Gridleak extracts amp parameters from original circuit schematics using AI vision — component values, gain staging, tone stack topology, tube types — then generates native preset files for every supported modeler. Every extraction is scored 0–100 and the score is published.